JP4859810B2 - Manufacturing method of wide shape retaining sheet - Google Patents

Description

  The present invention relates to a method for producing a wide shape-retaining sheet by connecting a plurality of stretched polyolefin resin sheets having a narrow shape-retaining property.

Since the shape-retaining sheet is plastically deformed and retains the deformed shape after the deformation, the binding material (see, for example, Patent Document 1), the core material of the body fixing tool (for example, see Patent Document 2), and the shape retention. It is used for a type cap (for example, refer to Patent Document 3).
Japanese Patent No. 3582854 JP 2004-57509 A Japanese Patent Laid-Open No. 11-93012

The shape-holding sheet is, for example, “the thickness of the maximum thickness portion made of the polyethylene melt-solidified product by melting a general-purpose polyethylene having an intrinsic viscosity [η] of less than 3.5 dl / g and extruding it into a raw yarn or a raw belt shape. Is formed into a raw yarn or belt of 1 mm or more, and the return angle after 10 minutes from bending the stretched product 180 degrees at a temperature of 60 ° C. or higher and lower than the melting point of polyethylene is 20 degrees or less, and A method for producing a thread-like or belt-like plastically deformable polyethylene material, characterized by stretching until 90 minutes after the 90-degree folding, and the return angle after 15 minutes is 15 degrees or less "(see, for example, Patent Document 1). “A step of rolling a sheet mainly composed of high-density polyethylene having a weight average molecular weight of 500,000 or less and a step of stretching the rolled sheet, and the total stretching ratio is 10 times through the rolling step and the stretching step. Polyethylene binding tape manufacturing method characterized by uniaxially stretching the above. "(E.g., see Patent Document 4.) As proposed, it has been manufactured by drawing or rolling.
JP-A-11-222256

  That is, since the shape-retaining sheet is produced by stretching a polyolefin resin sheet at a high magnification, it is impossible to obtain a wide shape-retaining sheet. It is difficult to manufacture because it must be manufactured by fixing it with adhesive tape, stapler, etc., and the mechanical properties of the obtained product are not uniform and the performance is unstable and difficult to use .

  In view of the above problems, an object of the present invention is to provide a method capable of easily producing a wide shape-retaining sheet.

  In the manufacturing method of the wide shape maintaining sheet of the present invention, it is released after being bent at 180 degrees and 90 degrees and held for 1 minute, and the folding return angle θ when 5 minutes have passed after release is both 20 degrees or less. The side ends of a plurality of stretched polyolefin resin (melting temperature T1) sheets having shape-retaining properties are butted together and between the plurality of stretched polyolefin resin sheets and the second polyolefin resin (melting temperature T2) sheet. A wide shape in which a third polyolefin resin (melting temperature T3) sheet is melt extruded and a plurality of stretched polyolefin resin sheets and a second polyolefin resin sheet are laminated and fused via the third polyolefin resin sheet. A method for producing a holding sheet, wherein the melting temperature of each polyolefin resin is T1 ≧ T2 ≧ T3.

  The stretched polyolefin resin sheet used in the present invention is bent at 180 degrees and 90 degrees and held for 1 minute and then released, and the folding return angle θ when 5 minutes have elapsed after the release is both 20 degrees or less. It is a sheet having shape retention.

  The above-mentioned stretched polyolefin resin sheet has shape retainability, but the shape retainability is released after folding the stretched polyolefin resin sheet at 180 degrees and 90 degrees and holding it for 1 minute, and 5 minutes have passed since release. The bending return angle θ is 20 degrees or less, preferably the 180-degree bending return angle θ is 20 degrees or less, and the 90-degree bending return angle θ is less than 20 degrees, more preferably 180-degree bending. The return angle θ is 20 degrees or less and the 90-degree bending return angle θ is 15 degrees or less. If one of the 180 ° and 90 ° folding return angles θ, particularly the 180 ° folding return angle θ exceeds 20 °, sufficient shape retention may not be obtained.

  As the polyolefin-based resin constituting the stretched polyolefin-based resin sheet, any olefin-based resin having a film forming ability can be used. For example, a high-density polyethylene resin, a medium-density polyethylene resin, a low-density polyethylene resin, a linear low-density Polyethylene resin, polypropylene resin, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-pentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene -Vinyl acetate copolymer, ethylene- (meth) acrylic ester copolymer, ethylene-vinyl chloride copolymer, ethylene-propylene-butene copolymer, etc., and high-density polyethylene resin is preferably used .

  When the weight average molecular weight of the polyolefin resin is less than 100,000, the polyolefin resin becomes brittle, the stretchability is deteriorated, or a stretched polyolefin resin sheet having sufficient strength or creep resistance can be obtained. On the contrary, when it exceeds 500,000, the melt viscosity becomes high, the hot melt molding processability is lowered, and it becomes difficult to obtain a uniform sheet, so 100,000 to 500,000 is preferable. In the present invention, the weight average molecular weight is a value measured by gel permeation chromatography (GPC).

The melt index (hereinafter referred to as MI) of the polyolefin resin is preferably from 0.1 to 20 (g / 10 minutes), more preferably from 0.2 to 10 (g / 10 minutes), which is excellent in film moldability. It is. MI is an index representing the melt viscosity of a thermoplastic resin specified in JIS K 7210. Furthermore, in the case of a high density polyethylene resin, 0.94 g / cm ³ or more is preferable because the mechanical strength does not improve even if the density is reduced even if the density is reduced.

  As the stretched polyolefin resin sheet, a stretched polyolefin resin sheet having a shape-retaining property in which a polyolefin resin sheet having a weight average molecular weight of 100,000 to 500,000 is stretched at a stretch ratio of 5 times or more is preferable.

  In this case, the polyolefin resin is preferably a high-density polyethylene resin having an intrinsic viscosity [η] of less than 3.5 dl / g, such as glass fiber, talc, mica, calcium carbonate, magnesium hydroxide, alumina, zinc oxide, magnesium oxide, It is preferable to add inorganic machine fillers such as aluminum hydroxide, silica alumina, titanium oxide, calcium oxide, calcium silicate, basic magnesium carbonate, carbon fiber, and carbon black.

  The thickness of the polyolefin resin sheet before stretching is not particularly limited, but if it is too thick, stretching becomes difficult. Conversely, if it is too thin, the thickness of the polyolefin resin sheet after stretching becomes too thin. Since shape retainability is lowered, 0.2 to 15 mm is desirable.

  The stretching ratio is 5 times or more, and the stretched stretched polyolefin resin sheet only needs to have shape retention, but 10 to 40 times is preferable. The stretching method may be any conventionally known method, such as a method of stretching while heating with a heater or hot air by a uniaxial stretching method such as a roll uniaxial stretching method or a zone uniaxial stretching method. .

  When stretching uniaxially to a high degree of 10 to 40 times, a multistage uniaxial stretching method in which uniaxial stretching is repeated a plurality of times is preferable. When performing multistage uniaxial stretching, the number of stretching is preferably 2 to 20 times, more preferably 3 to 15 times, still more preferably 4 to 10 times.

  When performing multi-stage stretching by a roll uniaxial stretching method, it is desirable to install a feeding pinch roll, a take-up pinch roll, and at least one, preferably a plurality of contact rolls that rotate at a constant speed between these rolls. By installing such a contact roll, uniform stretchability is improved and stable stretch molding can be performed.

  The contact roll performs uniaxial stretching by applying a frictional force to the polyolefin resin sheet without being pinched. Further, the contact roll may be connected to the feeding roll and / or the take-up roll by a connecting member made of a gear, a chain, a pulley, a belt, or a combination thereof.

  The uniaxial stretching temperature cannot be uniformly stretched when it is low, and the sheet melts and cuts when it is high. Therefore, the range of “melting point−60 ° C.” to the melting point of the polyolefin resin of the polyolefin resin sheet to be stretched is more preferable, It is “melting point−50 ° C.” to “melting point−5 ° C.” of the polyolefin resin.

  Further, as a different preferred stretched polyolefin resin sheet, a polyolefin resin sheet having a weight average molecular weight of 100,000 to 500,000 was rolled to a rolling ratio of 5 times or more, and then the total stretching ratio was uniaxially stretched to 10 to 40 times. A stretched polyolefin resin sheet may be mentioned.

  The thickness of the polyolefin-based resin sheet before rolling is not particularly limited, but if it is too thick, stretching becomes difficult, and in the rolling process, a large pressing force is required to crush the polyolefin-based resin sheet with a rolling roll. Take-up force is required, and uniform rolling in the width direction may be difficult due to bending of the rolling roll, etc., conversely, if too thin, the thickness of the polyolefin resin sheet after stretching or rolling becomes too thin, Since not only uniform rolling becomes difficult, but also the rolling rolls come into contact with each other to shorten the life of the rolling roll, 0.2 to 15 mm is desirable.

  The polyolefin resin sheet is first rolled to a rolling ratio of 5 times or more. However, the rolling temperature cannot be uniformly rolled when the temperature is lowered, and melted and cut when the temperature is high. The range of “melting point −40 ° C.” to the melting point of the olefin resin of the polyolefin resin sheet is more preferable, and more preferably “melting point −30 ° C.” to “melting point −5 ° C.” of the olefin resin. In the present invention, the melting point refers to the maximum point of the endothermic peak that accompanies melting of the crystal, which is recognized when thermal analysis is performed with a differential scanning calorimeter (DSC).

  If the applied pressure (linear pressure) applied to the polyolefin resin sheet by the rolling roll is too small, it may not be possible to obtain a predetermined rolling magnification, and conversely if it is too large, not only will the bending of the rolling roll occur, Sliding easily occurs between the rolling roll and the raw sheet, and uniform rolling may be difficult. Therefore, the applied pressure is preferably 100 MPa to 3000 MPa, and more preferably 300 MPa to 1000 MPa.

  When the rolling ratio is less than 5 times, the effect of suppressing necking at the time of uniaxial stretching performed later cannot be obtained, high-strength uniaxial stretching cannot be performed, or the uniaxial stretching step Therefore, it is 5 times or more, preferably 7 times or more. There is no particular upper limit to the rolling ratio, but the higher the rolling ratio, the more load is applied to the rolling equipment, so 10 times or less is preferable.

  The rolling magnification is defined as (cross-sectional area of polyolefin resin sheet) / (cross-sectional area of polyolefin resin sheet after rolling), but the width of the polyolefin resin sheet hardly changes before and after rolling. (Thickness of resin sheet) / (thickness of polyolefin resin sheet after rolling).

  The rolled polyolefin resin sheet is then uniaxially stretched at a total stretch ratio of 10 to 40 times. The uniaxial stretching method is not particularly limited, and the above-described uniaxial stretching method may be adopted. Moreover, since the total draw ratio is 10 to 40 times, the uniaxial draw ratio may be determined so that the total draw ratio is within this range in consideration of the rolling ratio. Is not improved, it is preferably 1.3 times or more, more preferably 1.5 times or more, and still more preferably 1.8 times or more. Moreover, although an upper limit is not specifically limited, 4 times or less are preferable, More preferably, it is 3.5 times or less. The total draw ratio is a value obtained by multiplying the rolling ratio and the uniaxial draw ratio.

  In order to improve the dimensional stability of the stretched polyolefin resin sheet, the stretched polyolefin resin sheet may be annealed at a temperature of the melting point of the polyolefin resin from “melting point−60 ° C.” to the melting temperature or lower.

  If the annealing temperature is lowered, the dimensional stability will not improve, warping will occur if used for a long time, and if it is raised, the polyolefin resin will dissolve and the orientation will disappear and the tensile modulus, tensile strength, etc. will decrease. It is preferable that the resin be annealed at a temperature ranging from “melting point −60 ° C.” to the melting point and below the rolling temperature.

  Annealing is a heat treatment in the production line. When annealing, the stretched polyolefin resin sheet is stretched if a large tension is applied, and it is not tensioned or shrinks in a very small state. The length of the stretched polyolefin resin sheet in the stretching direction is preferably kept substantially unchanged, and it is preferable that no pressure is applied to the stretched polyolefin resin sheet. That is, it is preferable that the annealed stretched polyolefin resin sheet is annealed so that the length of the stretched polyolefin resin sheet before annealing is 1.0 or less.

  Accordingly, when the stretched polyolefin resin sheet is continuously annealed while being moved in the heating chamber with a roll such as a pinch roll, the feed rate ratio of the polyolefin resin sheet on the inlet side and the outlet side is 1.0 or less. It is preferable to anneal with setting.

  The heating method at the time of annealing is not particularly limited, and examples thereof include a method of heating with hot air, a heater, a heating plate, hot water or the like. The time for annealing is not particularly limited, and varies depending on the thickness of the stretched polyolefin resin sheet and the annealing temperature, but is generally preferably 10 seconds or more, more preferably 30 seconds to 60 minutes, and still more preferably 1 to 20 Minutes.

  The annealed polyolefin resin sheet may be further aged in a temperature range from 40 ° C. to the melting point of the polyolefin resin. The dimensional stability of the polyolefin resin sheet annealed by aging becomes more excellent.

  Aging is not a continuous treatment in the production line, but it is a relatively long time (minutes, time units) for heat treatment of single-wafers, scrolls, etc., once processed, such as cut winding, of a stretched polyolefin resin sheet. It means to lay down carefully and heat-treat.

  The aging temperature is the same as that left at room temperature when the temperature is low, and when it is high, it is thermally deformed, so the temperature range is from 40 ° C. to the melting point of the polyolefin resin, and the aging time is not effective in a short time and is too long. Even if an effect does not increase, 12 hours-7 days are preferable.

  The second polyolefin resin sheet used in the present invention supports a plurality of stretched polyolefin resin sheets whose side ends are butted together to form a wide shape retaining sheet, and the wide shape retention obtained. It is a sheet that acts as an adhesive when heat-sealing the sheet.

  The polyolefin resin constituting the second polyolefin resin sheet is the same as the polyolefin resin constituting the stretched polyolefin resin sheet, but the polyolefin resin constituting the stretched polyolefin resin sheet is the same as the polyolefin resin constituting the stretched polyolefin resin sheet. When the melting temperature is T1, and the melting temperature T2 of the polyolefin resin constituting the second polyolefin resin sheet, T1 ≧ T2, and a linear low density polyethylene resin is preferable.

  The thickness of the second polyolefin resin sheet is not particularly limited, but if it becomes too thin, it becomes difficult to support the stretched polyolefin resin sheet and it is difficult to adhere to the adherend. It is 150 micrometers, Preferably it is 20-80 micrometers.

  The third polyolefin resin sheet used in the present invention is a sheet for fusing the stretched polyolefin resin sheet and the second polyolefin resin sheet, and the polyolefin resin constituting the third polyolefin resin sheet. The resin may be the same as the polyolefin resin constituting the stretched polyolefin resin sheet, but the melting temperature is lower than the melting temperature of the polyolefin resin constituting the stretched polyolefin resin sheet and the second polyolefin resin sheet. A polyolefin resin having a temperature is used.

  That is, the melting temperature of the polyolefin resin constituting the stretched polyolefin resin sheet is T1, the melting temperature of the polyolefin resin constituting the second polyolefin resin sheet is T2, and the polyolefin resin constituting the third polyolefin resin sheet. When the melting temperature of the resin is T3, T1 ≧ T2 ≧ T3, and a low density polyethylene resin is preferable.

  In particular, since the third polyolefin-based resin is melt-extruded into a sheet and fused with the stretched polyolefin-based resin sheet and the second polyolefin-based resin sheet, those having a high melt index (MI) are preferable, and the MI is 15 A low density polyethylene resin of ~ 35 (g / 10 min) is preferred.

  In the present invention, the side ends of the stretched polyolefin resin sheet are butted together, and the third polyolefin resin sheet is melted between the butted stretched polyolefin resin sheets and the second polyolefin resin sheet. A plurality of stretched polyolefin resin sheets and a second polyolefin resin sheet are laminated and fused via a third polyolefin resin sheet by extrusion. When the side ends of the stretched polyolefin resin sheet are butted together, it is preferable that the stretched polyolefin resin sheet is butted so that the stretching directions thereof are parallel to each other.

  Next, the manufacturing method of the wide shape maintenance sheet | seat of this invention is demonstrated with reference to drawings. FIG. 1 is an explanatory view showing an example of a method for producing a wide shape-retaining sheet of the present invention. In the figure, 1 is a stretched polyolefin resin sheet, and 2 is a second polyolefin resin sheet.

  The second polyolefin resin sheet 2 is supplied to the first laminated roll 5. 7 is an extruder for a third polyolefin resin, which extrudes the third polyolefin resin into a sheet, and the extruded third polyolefin resin sheet 3 on the first laminating roll 5. Laminated and fused on the base resin sheet 2.

  Next, a plurality of stretched polyolefin resin sheets 1, 1,... Are placed on the third polyolefin resin sheet 3 so as to abut the side ends thereof so that the stretching direction and the sheet feeding direction are the same. Supplying and laminating and crimping with the 2nd lamination roll 51 and the 1st lamination roll 5 which were installed facing the 1st lamination roll 5, stretched polyolefin resin sheet 1, 1, ... and 1st 3 to obtain a wide shape retaining sheet 4. Reference numerals 6, 61 and 62 are guide rolls for appropriately supplying and feeding each sheet.

  FIG. 2 is a plan view showing an example of the obtained wide shape retaining sheet 4, and FIG. 3 is a cross-sectional view taken along the line AA in FIG. Three stretched polyolefin resin sheets 1, 1, 1 are bonded to the second polyolefin resin sheet 2 by the third polyolefin resin sheet 3, with their side ends abutting each other.

  Needless to say, the second polyolefin resin sheet 2 may be laminated on the other surface of the stretched polyolefin resin sheet 1.

  The structure of the manufacturing method of the wide shape maintenance sheet | seat of this invention is as the above-mentioned, and can manufacture a wide shape maintenance sheet | seat easily.

Next, examples of the present invention will be described, but the present invention is not limited to the following examples.
Example 1
A high-density polyethylene resin (manufactured by Nippon Polyethylene Co., Ltd.) having a weight average molecular weight (Mw) of 330,000 and a melting point of 135 ° C. is supplied to the same-direction biaxial kneading extruder (manufactured by Plastic Engineering Laboratory) and melt kneaded at a resin temperature of 200 ° C. After that, the melt-kneaded material was formed into a sheet having a width of 360 mm and a thickness of 2.4 mm using a calender molding machine in which the roll temperature was controlled at 110 ° C. to obtain a polyethylene resin sheet.

  The obtained polyethylene resin sheet was rolled at a rolling ratio of 9.2 times using a rolling molding machine (manufactured by Sekisui Koki Co., Ltd.) heated to 125 ° C. to obtain a rolled polyethylene resin sheet having a thickness of 0.25 mm. The obtained rolled polyethylene resin sheet was subjected to a multistage stretching of 1.95 times with a hot air heating type multistage stretching apparatus (manufactured by Kyowa Engineering) heated to 110 ° C., a total stretching ratio of 18 times, a width of 280 mm, and a thickness of 0 A 18 mm stretched polyethylene resin sheet was obtained.

  The obtained stretched polyethylene resin sheet was supplied with a pinch roll to a hot air heating tank with a line length of 19.25 m set at 125 ° C. at an inlet speed of 2.75 m / min, and an outlet speed of 2.75 m / min. Set to, and then subjected to primary annealing for 7 minutes, followed by secondary annealing in the same manner to obtain an annealed stretched polyethylene resin sheet, which is then fed to a constant temperature bath at 60 ° C. and aged for 24 hours, An aged stretched polyethylene resin sheet was obtained.

  The obtained stretched polyethylene resin sheet was cut into a width of 1 cm and a length of 15 cm, bent at 180 degrees and 90 degrees and held for 1 minute, then released, and the folding return angle θ after 5 minutes from the release was measured. However, it was 4 degrees and 7 degrees.

  Using the obtained stretched polyethylene resin sheet and a linear low density polyethylene resin sheet having a thickness of 60 μm (manufactured by Sekisui Film Co., Ltd., melting point 121 ° C.), the shape-retaining sheet 4 was obtained with the apparatus shown in FIG.

The linear low density polyethylene resin sheet 2 is supplied to the first laminating roll 5 and is extruded on the first laminating roll 5 by the extruder 7. The low density polyethylene resin having a thickness of 15 μm (manufactured by Nippon Polyethylene Co., Ltd., melting point 105 C., M1 = 20 (g / 10 min)) Sheet 3 is laminated and fused, and then three stretched polyethylene resin sheets 1, 1, 1 are abutted so that the side ends thereof have the same stretch direction. Thus, the sheet was supplied on the low density polyethylene resin sheet 3 and laminated, and the first laminated roll 5 and the second laminated roll 51 were pressure-bonded to be fused to obtain a wide shape maintaining sheet 4.

  The obtained shape-holding sheet was bent at 180 degrees and 90 degrees and held for 1 minute, then released, and the bending return angle θ when 5 minutes passed after the release was measured to be 4 degrees and 7 degrees, respectively. .

It is explanatory drawing which shows an example of the manufacturing method of a wide shape maintenance sheet | seat. It is a top view which shows an example of the obtained wide shape maintenance sheet | seat 4. FIG. It is AA sectional drawing in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stretched polyolefin-type resin sheet 2 2nd polyolefin-type resin sheet 3 3rd polyolefin-type resin sheet 4 Wide shape maintenance sheet

Claims (3)

  Folded at 180 degrees and 90 degrees and held for 1 minute, then released, and a plurality of stretched polyolefin-based resins (melted) having a shape-retaining property where the folding return angle θ is less than 20 degrees when 5 minutes have passed after release. Temperature T1) The side edges of the sheet are butted together, and a third polyolefin resin (melting temperature T3) sheet is interposed between the plurality of stretched polyolefin resin sheets and the second polyolefin resin (melting temperature T2) sheet. A method for producing a wide shape-retaining sheet, in which a plurality of stretched polyolefin resin sheets and a second polyolefin resin sheet are laminated and fused via a third polyolefin resin sheet by melt extrusion, each polyolefin resin The method for producing a wide shape-retaining sheet is characterized in that the melting temperature of T1 ≧ T2 ≧ T3.   The stretched polyolefin resin sheet is a polyolefin resin sheet having a weight average molecular weight of 100,000 to 500,000, stretched to a stretch ratio of 5 times or more, bent at 180 degrees and 90 degrees, held for 1 minute, and then released. 2. The method for producing a wide shape-retaining sheet according to claim 1, wherein the folded polyolefin resin sheet has shape-retaining properties in which both folding return angles [theta] are 5 [deg.] Or less when 5 minutes have passed after release. .   After the polyolefin resin sheet having a weight average molecular weight of 100,000 to 500,000 is rolled to a rolling ratio of 5 times or more, the stretched polyolefin resin sheet is uniaxially stretched to 10 to 40 times, 180 degrees And it is a stretched polyolefin resin sheet having a shape-retaining property in which the folding return angle θ is 5 degrees or less when 5 minutes have passed after being released after being bent and held at 90 degrees for 1 minute. The manufacturing method of the wide shape maintenance sheet | seat of Claim 1.

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